1. Field of the Invention
The present invention relates, in general, to an apparatus and method for displaying a bird's eye view image of around a vehicle by converting images photographed by a plurality of cameras and then synthesizing the converted images. More particularly, the present invention relates to an apparatus and method for displaying a bird's eye view image, which facilitates perceiving a three-dimensional obstacle present on a seam of the image.
2. Description of the Related Art
As is well-known in the art, there are various methods of displaying situations around a vehicle using a bird's eye view which preferably make use of surrounding images that are photographed by a plurality of on-vehicle cameras. Specifically, these methods perform image conversion that include correction of distortion, change of viewpoint, and display area trimming on the surrounding images, and then suitably connect and synthesize the images into one continuous bird's eye view image.
However, a three-dimensional obstacle adjacent to the vehicle is displayed as a “completely-fallen image” on a bird's eye view and thus can be hardly discriminated from a shape on a road (e.g., a traffic sign). In particular, if a three-dimensional obstacle is suitably placed on or around a seam, three-dimensional images of the obstacle taken by adjacent cameras may be “completely fallen” in different directions and overlap each other. Accordingly, the obstacle is harder to perceive.
As an attempt to overcome this problem, Korean Patent Application Publication No. 2002-019556, incorporated by reference in its entirety herein, is directed to a technique that awakens a driver's attention by displaying a “completely-fallen” three-dimensional obstacle image on a seam of a bird's eye view image, when photographed in common by adjacent cameras, without smoothing (i.e., blending of) the seam. (Refer, for example, to FIG. 5 (C), described herein.)
According to this method, however, an important portion of the bird's eye view image is in a scattered state since the seam is not suitably smoothed. Accordingly, the perceptibility of the obstacle may be degraded.
In addition, as illustrated in FIG. 1 (A) through (E), Korean Patent Application Publication No. 2006-(12)1587, incorporated by reference in its entirety herein, discloses a technique that continuously or intermittently changes the position of seams 70 of a bird's eye view image, including a road 5 and the area surrounding a vehicle 20.
This technique requires the position of the seams to be changed in real-time even if an obstacle is not present around the vehicle, thereby increasing processing load as a drawback.
Further, Korean Patent Application Publication No. 2007-036668, incorporated by reference in its entirety herein, discloses optimally changing the position of a seam of a bird's eye view image on the horizon or the ground level by suitably determining the motion of the vehicle based on information from a steering angle sensor, a vehicle speed sensor, a shift position sensor, and the like. In this case, processing load increases since the change of the position of the seam is suitably required to be processed in real-time even if an obstacle is not present around the vehicle.
Korean Patent Application Publication No. 2007-041791, incorporated by reference in its entirety herein, discloses changing the position of a seam of a bird's eye view image on the horizon or the ground level when an on-vehicle sonar suitably detects an obstacle present on the seam of the bird's eye view image. Here, processing load further increases since the on-vehicle sonar must be equipped.
Accordingly, as described by above mentioned references, as the position of a seam moves, an image on one side of the seam suitably increases from the “completely-fallen shape,” whereas an image on the other side of the seam suitably disappears from the top portion of the “completely-fallen shape.” As a result, the perceptibility of an obstacle is not always improved.
Further, a three-dimensional obstacle suitably placed adjacent to a seam of a synthesized image may not be continuously connected on the seam, may be distorted even if connected on the seam, or may not be displayed at all. As a result, the perceptibility of the obstacle is not always improved.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.